CSD97395Q4M: CSD97395/CSD95373 Undershoot Spec

Yazhu Liu

Part Number: CSD97395Q4M
Other Parts Discussed in Thread: TPS53626

Hi Team,

When testing CSD97395/CSD95373, our customer found that the SW node undershoot less than -0.3V is longer than 10ns, please refer to the waveform below.(They use TPS53626+CSD97395/CSD95373)

On the datasheet, it says that Vsw shouldn't be under -7V for longer than 10ns. Could you please have a look at the waveform above and give some comments about will this undershoot cause any damage to the device?

Thanks.

Best Regards,

Livia

over 5 years ago

0 Bo Wang4 over 5 years ago

TI__Prodigy 405 points

Hi Livia,

The -0.3V spec on datasheet is DC spec instead of AC. During dead times before and after FET switching, both high-side and low-side FETs are off, LS body diode is conducting the load current, you will see around -0.7V body diode voltage on Vsw waveform depending on load current.

To check your waveform, could you please send one picture with zoom-in falling edge?

Thanks!

Best regards

0 Yazhu Liu over 5 years ago in reply to Bo Wang4

TI__Intellectual 1410 points

Hi Bo,

Thank you for the quick reply.

Please refer to the zoom-in waveform as below.

The minimum voltage is -2.016V and the duration below -0.3V is 13.45ns.

Best Regards,

Livia

0 Bo Wang4 over 5 years ago in reply to Yazhu Liu

TI__Prodigy 405 points

Hi Livia,

The waveform is normal. This negative voltage is LS body diode conduction during falling edge dead time.

Thanks!

Best regards

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CSD97395Q4M: CSD97395/CSD95373 Undershoot Spec